In February of 2007, the U.S Department of Energy’s (DOE) Energy Information Administration (EIA) released a report1 detailing historical energy prices, as well as forecasting the energy market over the next 23 years. The report confirms that today’s facility managers are faced with the task of striking a delicate balance between maintaining building performance and keeping operating costs within budget.

To achieve this balance while remaining fortified against escalating energy costs, facility managers must implement a series of innovative strategies and tactics to reduce energy consumption in the context of today’s volatile energy market. In the hope that the old adage, “an ounce of prevention is worth a pound of cure,” holds true, most facility managers are looking to building systems and high- performance products as their first line of defense against rising energy costs.

When looking for prevention tactics, many facility managers initially focus on the low-hanging fruit of lighting retrofits, HVAC upgrades, and other electric-component upgrades to reduce energy consumption. However, with round one of their energy-reduction activities behind them, many managers find themselves searching for other ways to further reduce the energy consumption of their buildings. In response to this growing demand, many of today’s top roofing manufacturers have stepped up to the plate by designing long-lasting waterproofing systems that can also reduce energy consumption.

Specifications for Energy Performance
Designing a roofing system that focuses on energy reduction demands a customized specification that concentrates on the performance of the roofing system and the selection of proper roofing components to maximize energy performance.

When looking at a typical roofing system, each of the following components offers opportunities for specifying high levels of product performance, including energy-saving benefits.

Although each individual component has the potential to contribute to overall energy performance, the major contributors in the system are the insulation and the roof system. The remaining components contribute immeasurably, albeit less directly, to reduced energy consumption by extending the working life of the roof — which is arguably the single greatest contribution to sustainability that quality roofing solutions can provide.

Roofing Insulation
Insulation’s impact on the roofing system can be validated by numerous studies that have been performed by a variety of organizations, including roof system manufacturers. These studies demonstrate the effect of increasing the thickness of roof insulation on energy consumption. A recent study conducted by the Energy Services Provider Group (ESPG) for the Polyisocyanurate Insulation Manufacturers Association (PIMA) looked at the amount of polyiso insulation installed across the U.S. on low-slope roofs between 1999 and 2003. According to the study, insulation alone saved more than 217 million barrels of oil and $8.7 billion in energy costs. 2

Furthermore, the study also assessed the impact of increasing the insulation levels by one-inch beyond the code minimum. It found that the effect of such an increase would be an additional $2.5 billion in energy-cost savings, and an additional reduction of 64 million barrels of oil.

No doubt as a result of this and similar studies, the Atlantabased American Society of Heating, Refrigerating and Air- Conditioning Engineers (ASHRAE) recently proposed increases to the minimum required roof- and wall-insulation levels in Standard 90.1, which is the national model energy code for commercial buildings. In the proposal, the abovedeck roof insulation requirements would increase from R-15 to R-20. R-value measures the heat conductivity of material: the higher the R-value, the more effective the heat transference of the insulation. ASHRAE’s proposed increase represents a 33% increase in Standard 90.1. The proposal is expected to be included in the 2010 revision of ASHRAE Standard 90.1.

In addition to energy performance, when specifying the type and thickness of the insulation to be installed above the roof deck, the following characteristics should be considered:
• R-value per inch of material
• Moisture resistance
• Roofing system compatibility
• Resistance to solvents used in construction adhesives
• Dimensional stability
• Performance in fire tests – FM®3 Class Approvals 1(FM 4470) and UL 1256
• Long-term R-value (ability to retain initial R-value)
• Recycled content

“Cool” Surfacing
According to the Cool Roof Rating Council® (CRRC), although the definition of a “cool roof” may vary when applied to different codes or programs, in simplest terms: “a cool roof reflects and emits the sun’s heat away from the surface of the roof, instead of transferring it to the building below.” This lack of heat transfer reduces roof-top temperatures and decreases the amount of HVAC-system energy required to cool the interior of the building, resulting in energy savings.

As facility managers increasingly specify reflective roof surfaces, there are two resources that provide third-party testing for a variety of roofing systems. One of the most predominant organizations using independent test data is the CRRC. The CRRC is an independent and non-biased organization that has established a rating system for displaying accurate radiative property data on the outermost layer of roof surfaces. The core of the CRRC is its Product Rating Program, through which roofing product manufacturers can label their products with solar reflectance and thermal emittance values, as measured by CRRC Accredited Independent Testing Laboratories.

Another independent organization dedicated to helping the U.S. reduce its energy consumption is the ENERGY STAR® program, which was developed through a joint effort between the U.S. Environmental Protection Agency (EPA) and the DOE. The EPA and DOE joined forces to develop the ENERGY STAR program due to the fact that the majority of the United States’ electricity is generated by the environmentally harmful burning of fossil fuels. The EPA’s involvement is derived from the fact that reducing the amount of energy needed to cool buildings has a direct effect on the reduction of the production of air pollutants.

Included in the ENERGY STAR program is Version 2.0 Specification for Roof Products. This specification outlines the performance and testing requirements that qualifying roof products must meet in order to earn the ENERGY STAR performance-based qualification.

In addition to individual product information, The U.S. Green Building Council’s (USGBC) Leadership in Energy and Environmental Design® (LEED®) Green Building Rating System™ provides a benchmark for the design, construction, and operation of high- performance green buildings. Roof surfacing can play a very vital role in helping facilities earn a LEED certification level of Certified, Silver, Gold, or Platinum. For example, reflective roof systems contribute valuable LEED points by reducing the urban heat island effect and increasing energy performance. Vegetative surfacing on roof systems offers additional potential for obtaining LEED points through storm water management and protection of habitat. For more information on the LEED programs, visit the USGBC’s Web site at: www.usgbc.org.

Calculating the Savings
On the Web, there are a variety of tools available to estimate the cost savings of the proper specification of insulation and membrane surfacing. These tools evaluate the annual cost savings based on your specified roofing system, and will help you to prepare return on investment (ROI) strategies that justify the initial capital expenses associated with the increased energy performance. In order of their complexity (from least to most), here are some calculators that may be useful:

• The ENERGY STAR’s Roof Comparison Calculator (www.roofcalc.com) estimates annual energy savings for typical building types with non-metallic roofs using typical weather conditions. These estimates are derived from simulations run with the DOE-2.1E model using cooling and heating degree-days.

• The DOE’s Cool Roof Calculator was developed by the DOE’s Oak Ridge National Laboratory (ORNL). These calculations require more input data, and there are 243 different locations built into the pull- down lists in the calculator. There are two additional calculators available, both of which are based on facility size:

• For large facilities (Version 2.0): www.ornl.gov/sci/roofs%2Bwalls/facts/CoolCalcPeak.htm;

• For small and medium-sized facilities (Version 1.2) www.ornl.gov/sci/roofs%2Bwalls/facts/CoolCalcEnergy.htm.

In addition to the above energy calculators, many trade associations, such as the National Roofing Contractors Association (NRCA), have their own online calculators to help in the specification and design of an energy-efficient roofing system. As with any online calculator, actual energy savings may vary when differentiating criteria, such as building design, building operation, cooling and heating equipment, and local weather are factored in.

Other Considerations
As the surfacings of low-slope roof systems experience normal wear and tear, there will be some degradation of roof reflectivity. This reduction can be attributed to the fact that low-slope roofs have the tendency to accumulate dirt and debris because their slope is not great enough to allow dirt removal from rain runoff. To preserve reflectivity of the surfacing, it is important to follow maintenance procedures as specified by the roofing manufacturer. Proper maintenance minimizes degradation of the surfacing and maximizes energy savings, resulting in excellent building protection to optimize financial return on the building owner’s investment.

Conclusion
In order to successfully navigate the volatility of today’s energy market, it is not enough that a properly specified roof system provide a long-lasting waterproofing system; it must also act as an energy conservation tool. With natural energy costs progressively increasing, the payback of incorporating additional insulation and “cool” surfacings will be well worth the increased initial capital investment, in comparison with traditional systems. More than ever before, today’s facility managers have at their disposal a diversified arsenal of innovative products and tools that will allow them to effectively lower the overall cost of operating their facilities during periods of peak energy demand.

1 The report can be found at: www.eia.doe.gov/oiaf/aeo/.

2 An overview of the PIMA study can be found at: www.polyiso.org/NewsFiles/Press_BarrelsOil_new.pdf.

3 FM is a registered trademark of Factory Mutual Global.

Tom Bauer is a product manager for The Garland Company, Inc., a Cleveland-based manufacturer of highperformance roofing materials.

Back to top ▲